The focus of this proposed research is to determine underlying causes for the enhancement of osteointegration by calcium phosphate materials. The materials are currently being used as coating for orthopaedic implants to accelerate initial bony attachment. The underlying mechanisms related to the effect of calcium phosphate on osteoblast response and thus the effect on the osteointegration process is yet to be understood. This research aims to examine two factors which may alter osteoblast activity: 1) the effect of calcium phosphate degradation and reprecipitation products on media composition and 2) the effect of calcium phosphates on molecular conformation. In the first part of the proposed research, calcium phosphate influence on media composition will be studies using different initial media conditions to promote calcium phosphate dissolution and growth. Subsequently, osteoblasts will be subjected to calcium phosphates and these different media compositions. Secondly, the effect of calcium phosphates on molecular conformation will be investigated using synthetic peptides The conformation of these peptides on calcium phosphate and tissue culture plastic surfaces as well as osteoblast response to these peptide altered surfaces will be determined. In future studies, information gained from this research will be used to design optimal calcium phosphate materials and to investigate the interaction of extracellular matrix molecules, such as osteopontin, with calcium phosphates.